fix(Columns): Allow Columns to accept a className prop

react/Columns/Columns.js

@@ -5,17 +5,26 @@ import PropTypes from 'prop-types';
 import classnames from 'classnames';
 
 const renderColumn = (el, index) => (
-  <div key={index} className={styles.column}>{el}</div>
+  <div key={index} className={styles.column}>
+    {el}
+  </div>
 );
 
-export default function Columns({ children, tight, flexible, reverse }) {
+export default function Columns({
+  children,
+  tight,
+  flexible,
+  reverse,
+  className
+}) {
   return (
     <div
       className={classnames({
         [styles.columns]: true,
         [styles.columns_tight]: tight,
         [styles.columns_flexible]: flexible,
-        [styles.columns_reverse]: reverse
+        [styles.columns_reverse]: reverse,
+        [className]: className
       })}>
       {children.map(renderColumn)}
     </div>
@@ -26,7 +35,8 @@ Columns.propTypes = {
   children: PropTypes.array.isRequired,
   tight: PropTypes.bool,
   flexible: PropTypes.bool,
-  reverse: PropTypes.bool
+  reverse: PropTypes.bool,
+  className: PropTypes.string
 };
 
 Columns.defaultProps = {